revert to dev version
revert to dev version

jhamman/xarray,chunweiyuan/xarray,jhamman/xarray,markelg/xray,shoyer/xray,pydata/xarray,xray/xray,shoyer/xarray,pydata/xarray,pydata/xarray,markelg/xray,jhamman/xarray,jhamman/xray,shoyer/xarray,markelg/xray